Front head for rock-drills



L. C. BAYLES.

FRONT HEAD FOR ROCK DRILLS. APPLICATION FILED JULY 6.1920.

lNvE TOR .afm d j BY:

L) AToRNl-:Y

UNITED STATES PATENT OFFICE.

lLEWIS CONDICT IBAYLS, 0F EASTON, PENNSYLVANIA, ASSIGNOR T0 INGERSOLL- RAND COMPANY, 0F JERSEY CITY, NEW JERSEY, A. CORPORATION 0F NEW JERSEY.

`IERONII HEAD FOR ROCK-DRILLS.

To all 'whom 'it may concern Be it known that I, LEWIS C. BAYLEsa citizen of the United States, residin at Easton, in the county of Northampton, tate of Pennsylvania, have invented -a certain new and useful Improvement in Front Heads for Rock-Drills, of which the followingis a specification.

his invention relates to a removable front head for rock drills of the hammer type, in which a renewable bushing is ordinarily inserted in the bore of the front head, through which the shankof the drill steel is adapted to extend into position to receive the impact blow of the hammer.

In spite of every reasonable precaution, and the skill of the best blacksmiths, a drill steel will occasionally befurnished to'the drill operators having a relatively soft shank, which will swell or become upset at the end being struck by the hammer, so that it becomes impossible to withdraw the steel axially or longitudinally through the chuck or bushing in the head. Under such circumstances, whether the miner is using a rock drill having a solid front head or a bushed front head, it becomes necessary to remove a portion of the front of the rock drill, lay the drill steel on a piece of track or other support to form an anvil, and pound the upset portion of the shank until the end is small enough to pass through the solid front head or the bushing, as the case may be, after which the machine is reassembled and the work is continued. The `operation described is troublesome and vexations even with a hexagon shank, but particularly difiicult with a cruciform shank and in any case much valuable time is lost.

The primary object of the present invention, is to overcome the difficulty of removing an upset drill steel from the bushing in the front head by an improved front head construction having a split bushing which may be removed from the drill steel after the steel and bushing have been removed lfrom the front head. Another steel may then be inserted in the machine and the work continued.

Another object of the invention is to construct the split bushing in such manner that it will sustain and afford resistance to side thrust Without, however, weakening the front head.

To these and other ends, the invention con- Specication of Letters Patent.

ratenteaoct. 11, 1921.

Application led July 6, 1920. Serial No. 394,193.

sists of the preferred construction of front head shown in the accompanying drawings, in which,

Figure l is a side elevation of a stoping drill selected to illustrate the invention;

.F ig. 2 is an enlarged transverse sectional view through the front head on the line 2 2 of Fig. l looking in the direction of the arrows;

Fig. 3 is a longitudinal sectional view through the front head on the line 3 3 of Fig. 2 looking in the direction of the arrows, and

Fig. 4 is a detail perspective view showing the two parts of a split bushing lying side by side-before assembly.

Referring to the drawings, Fig. l represents a stoping drill .having the hammer cylinder A to which a front head B is removably connected in the usual manner as by means of the side bolts C. The rock drill is -also provided with the usual feed cylinder D and other operative parts which it 1s not necessary to mention or describe as they form no part of the present invention. A drill steel E, in this instance of hexagonal form, has been chosen by way of example to illustrate the invention.

The front head B is provided with a bore F adapted to receive a renewable bushing illustrated in detail in Fig. 4, having a uni- -form bore through which the shank of the metrical sections adapted to fit together i along the roughened split surfaces H and remain rmly in contact when the shank of the drill steel E is inserted in the said bush- 1n ne suitable method of splitting the c lindrical sleeve to form the two portions Jy and K of` the bushing, is to cut or otherwise form longitudinal grooves in the walls of the sleeve as illustrated at L to a suficient depth to permit the sleeve to be split apart by a Wedge or other means. The walls of the bushing are thus partially cut and partially split or broken along the lines of cleavagev and the roughened split surfaces are preferably left untouched so that the two halves of the bushing will it tightly together within the bore of the front head. The bushing formed of the two parts .l and K, although split apart, affords resistance to side thrust of the drill steel without weakening the front head, and a drill steel, which has become upset at the end 0 and cannot be withdrawn axially through the bushing, may be removed from the bushing by separating the two sections d and K after removal from the front head.

The front head B may be of the usual form having a longitudinal split or openirli P along one side. rl`he split bushing J, is preferably inserted into the front head up to the shoulder R and suitable means are provided for holding the bushing in the bore of the front head. ln this instance the transverse locking bolt S having the nuts T and the wedge-shaped body portion U serves to hold the sections of the bushing in position by engagement with the notches V on each section.,

bviously, the construction may be modified without departing from the invention as described and claimed herein and l am not to be understood as limiting the invention to the details shown in the drawings which illustrate one preferred embodiment.

l claim:

1. A front head construction for a rock drill of the hammer type, said front head provided with a bore adapted to receive a renewable bushing having a uniform bore through which the shank of the drill steel is adapted to extend, said bushing being formed from a hollow cylindrical sleeve having the metal of its walls at diametrically opposite points weakened and split apart along longitudinal lines to form two substantially symmetrical sections adapted to ft together along the roughened split surfaces and remain rmly in contact when the shank of a drill steel is inserted in the said split bushing, and means for holding said split/bushing in the bore'of the front head, whereby the bushing aifords resistance to side thrust and permits removal of a drill steel which has been upset at the end.

2. A front head construction for a rock drill of the hammer type, said front head provided with a bore adapted to receive a renewable bushing having a uniform bore through which the shank of the drill steel is adapted to extend, said bushing being formed from a hollow cylindrical sleeve having the metal of its walls at diametrically opposite points weakened and split apart along longitudinal lines to form two substantially symmetrical sections adapted to fit together along the roughened split surfaces and remain firmly in contact when the shank of a drill steel is inserted in the said split bushing, and a locking bolt extending transversely through the wall of the front head and engaging notches in both of said bushing sections for holding said bushing sections in the front head, whereby the bushing affords resistance to side thrust and permits removal of a drill steel which has become upset at the end.

ln testimony whereof I have specification. LEWllS CONDlCT BAYLES.

signed this 

